International roaming and more generically, the bridging of calls across telecommunications networks is well detailed in the prior art literature related and industry know-how. For instance, U.S. Patent Application Pub. No. 2002/0061745 by Ahn et al., entitled Roaming Service System for GSM Service Subscriber in CDMA Service Area, and Method for Registering Locations and Transmitting and Receiving Signals and Short Messages using the System, calls for the installation of a GSM-type SIM card into the CDMA terminal; our invention of present however remains independent of any such subscriber modification and/or registration.
Similarly, U.S. Pat. No. 6,075,855 to Christiansen et al., entitled Method of Accessing a SCP in an ISUP Network with Partial Release details art relevant to call set-up and clearing for intermediate access to a SCP in an ISUP network. Nevertheless, the art disclosed therein remains tied to the loop-back (‘hairpin’) trunk technique; a highly undesirable technique given today's telecommunications infrastructure, as it redundantly ties up trunks and related network resources. Indeed the art of the present invention remains independent of any such looping and goes beyond much of the obviousness of that disclosed art. Other related technology, as U.S. Pat. No. 6,393,289 to Bunting et al., entitled Apparatus, Method and System for Wireless Telecommunication Session Control by an Adjunct Network Entity, revolves around the interpretation of an ANSI-41 command by an network adjunct. Under that disclosure, the network adjunct will in turn allow the call to proceed, hair-pin the call, or invoke other ANSI-41 directives in order to instruct the switch to route the call without hair-pining the call through the network adjunct.
REFERENCES CITED:U.S. patent application20020061745May 2002Ahn et al.455/432U.S. Pat. No. 6,393,289May 2002Bunting et al.455/445U.S. Pat. No. 6,075,855June 2000Christiansen et al.379/209.01Other References    GSM 03.90, Digital cellular telecommunications system (Phase 2+); Unstructured Supplementary Service Data (USSD)—Stage 2    GSM 09.02, Mobile Application Part (MAP) specification    3GPP2 N.S0023, Network Support for MDN-Based Message Centers    TIA TR 45.2, IS-841, TIA/EIA-41-D Based Network Enhancements for MDN Based Message Centers    TIA/EIA ANSI-41 Cellular Radiotelecommunications Intersystem Operations